1. Field of the Invention
The present invention relates to an input/output device that is portable and can be used for inputting and outputting.
2. Description of Related Art
A typical input mechanism is a keyboard. Other simple input devices include a mouse, a track ball, a touchpanel, a tablet and the like. A typical output mechanism is a printer, including desk top types such as an electrophotography system or an ink jet system, or a display device, such as a liquid-crystal display panel.
The conventional keyboard is limited with respect to miniaturization and the input of figures. The mouse has difficulty in inputting characters and can not be used if a flat plane does not exist. The track ball has difficulty in inputting characters and also has a defect in that fine inputting cannot be performed. The touchpanel and the tablet require a large area and are difficult to reduce in size.
Also, regarding output mechanisms, the electrophotography system and the ink jet system in desk top type devices have been developed toward miniaturization but are still inconvenient for carrying. Also, display devices, such as the liquid-crystal display panel, cannot provide a hard copy of the display.
To solve the above-mentioned problems, an electronic pen that functions as an input/output device having a rod or pillar-like external shape and is portable has been provided with an input mechanism and an output mechanism on both ends. However, this electronic pen has a limited external dimension and weight to enable a user to hold it by hand. Consequently, the internal battery for driving must be made small, which is disadvantageous because then the capacity of the battery is small and the time for its continuous use is limited.